PERCY JACKSON AND THE OLYMPIANS (THE ULTIMATE GUIDE), by Mary-Jane Knight. Designed by Philip Chidlow. (Disney-Hyperion, $12.99.) Gods, beasts and tips for children with an immortal parent, based on Rick Riordan’s series. (Ages 10 and up)

Rankings reflect sales reported by vendors offering a wide range of general interest titles. The sales venues for print books include independent book retailers; national, regional and local chains; online and multimedia entertainment retailers; supermarkets, university, gift and discount department stores; and newsstands. E-book rankings reflect sales from leading online vendors of e-books in a variety of popular e-reader formats.

E book sales are presently included for all adult categories (fiction, non-fiction and advice) except for graphic novels, and all children's categories with the exception of picture books. Titles are included regardless of whether they are published in both print and electronic formats or just one format. E-books available exclusively from a single vendor will be tracked at a future date.

The universe of print book dealers is well established, and sales of print titles are statistically weighted to represent all outlets nationwide. The universe of e-book publishers and vendors is rapidly emerging, and until the industry is settled sales of e-books will not be weighted.

The appearance of a ranked title reflects the fact that sales data from reporting vendors has been provided to The Times and has satisfied commonly accepted industry standards of universal identification (such as ISBN13 and EISBN13 codes). Publishers and vendors of all ranked titles conformed in timely fashion to The New York Times Best Seller Lists requirement to allow for independent corroboration of sales for that week.

Publisher credits for e-books are listed under the corporate publishing name instead of by publisher's division.

Sales of both print books and e-books are reported confidentially to The New York Times. The Best Seller Lists are prepared by the News Surveys and Election Analysis Department of The New York Times. Royalty Share, a firm that provides accounting services to publishers, is assisting The Times in its corroboration of e-book sales.

An asterisk (*) indicates that a book's sales are barely distinguishable from those of the book above. A dagger (†) indicates that some bookstores report receiving bulk orders.